Greases thickened with acyl ureas



United States GREASES THICKENED WITH ACYL UREAS Bruce W. Hotten, Orinda, Calif., assignor to California Research Corporation, San Francisco, Calif a corporation of Belaware No Drawing. Application June 28,1951,

Serial .No. 234,154

11 Claims. (Cl. 252-415).

rivatives of urea (e. g., octadecanoyl urea) represent a particularly effective class of thickening agents for grease compositions.

Metal soaps; such as calcium and lithium stearates, are examples of well-known agents which have been used and which are being used to thicken lubricating oils to the consistency of a grease. pro-oxidative, that is, increase the susceptibility of grease compositions to oxidation, it has been necessary to incorporate great amounts of oxidation greases.

The grease resistant to oxidation than those thickened with metal soaps, and also have increased melting points. Furtherinhibitors in these.

compositions of this invention aremore.

Because the metal soaps are more, the grease compositions described in this invention are more resistant to heat than soap thickened greases;

that is, at increased temperatures, the thickening agents of grease compositions of this invention do not lose their thickening action as rapidly assoaps do.

It is a tremendous advantage in lubricating systems which are not readily accessible to use grease compositions which withstand high temperatures and the effects of oxidations for long periods of time. Greases which are used to lubricate such parts as found in sealed bearings of electric motors, sealed bearings of compressors, rocker arms of airplane motors, numerous pieces of highspeed equipment, such as high speed motors, 'must' be resistant to oxidation while performing the specific task of-lubricating, and at the same time have high temperature stability.

Grease compositions have certain fundamental desir: able properties, and it is an object of this invention to prepare grease compositions in which the properties of the grease maybe retained throughout Wide'ranges of temperatures, pressures, and periods of time.

it is another object of this invention to prepare grease compositions which are not susceptible to the pro-oxidation action of metal soaps.

It isa further object of this invention to prepare grease compositions. which maintain their grease structure; throughout Wide changes in temperature.

These and. further objects of this invention will be apparent from the following description and the appended claims.

it has been discovered that greases can be prepared by the thickening action of acyl derivatives of urea and thiourea in an oil of lubricating viscosity. That is, an oil of lubricating viscosity can be thickened to the consistency of a grease by incorporating therein an acyl urea or an acyl thiourea.

The grease compositions of this invention comprise mainly oils of lubricating viscosity and acyl ureas and/ or acyl thioureas. Restated, our agents have an essential nucleus, a urea or thiourea. with at least one of the amino groups containing an acyl group attached thereto. As between the acyl ureas and the acyl thioureas, the acyl ureas are preferred.

The acyl ureas and thioureas include (1) acyl ureas and thioureas having one acyl radical in the molecule, that acyl radical being attached to a nitrogen atom, (2) acyl ureas and thioureas having two acyl radicals in the molecule, only one acyl radical being attached to each nitrogen atom (these acyl radicals may or may not be alike), and (3) acyl ureas and thioureas having one acyl radical attached to one nitrogen atom, and an essen- 2'. tially hydrocarbon acyclic radical attached to the other nitro gen atom.

The acyl ureas of this invention contain a total of from 11 to 27 carbon atoms. That is, in addition to the carbon atom in urea itself, the acyl ureas contain from l0to 26 carbon atoms. Because of the increased eifectiveness derived therefrom as thickening agents of lubricating oils, it is preferred that the acyl urea contain only one. acyl radical in the molecule; that is, in the preferred acyl urea molecule, one nitrogen atom is attached to one acyl radical, and the other nitrogen atom is attached to two hydrogen atoms. It is preferred that this particular acyl urea contain from 12 to 18 carbon atoms in the acyl radical.

Examples of acyl radicals includethose ,derivedfrom the following fatty acids: formic acid, acetic acid, butanoic acid, pentanoic acid, hexanoic acid, octanoic acid, fdecanoic acid,y-undecanoic acid, "dodecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, mixtures of fish oil fatty acids,xetc.

Examples of essentially hydrocarbon acyclic radicals include the radicals derived from methane, ethane, ethene,

propane, propene, butane, butene, pentane, hexane, isohexane, heptane, isoheptane, octane, isooctane, decane, dodecane, tetradecane, hexadecane, octadecane, eieosane, docosane, etc.

Examples of acyl ureas and acyl thioureas which can be used according to this invention include decanoyl urea, decanoyl thiourea, undecanoyl urea, dodecanoyl urea,. dodecanoyl thiourea, hexadecanoyl urea, hexadecanoyl thiourea, heptadecanoyl urea, octadecanoyl urea, octadecanoyl thiourea, dipentanoyl urea, dihexanoyl urea, dihexanoyl thiourea, diheptanoyl urea, didecanoyl urea, didecanoyl thiourea, l-pentanoyl-3-hexanoyl urea, l-pentanoyl-3-hexanoyl thiourea, l-pentanoyl-3-heptanoyl urea, l-hexanoyl-3-decanoyl urea, l-hexanoyl-3-decanoyl thiourea, 1-hexanoyl-3-eicosanoyl urea, l-octanoyl-3- octadecanoyl urea, l-rnethyl-3-eicosanoyl urea, l-ethyl-3- hexadecanoyl urea, 1-ethyl-3-hexadecanoyl thiourea, 1- ethyl-3-eicosanoyl urea, l-ethyl-3-docosanoyl urea, 1- amyl-3-decanoyl urea, l-amyl-3-decanoyl thiourea, 1- hexyl-3-decanoyl urea,v 1-hexyl-3-octadecanoylurea, l hexyl-3-eicosanoyl urea, etc.

The term essentially hydrocarbon means those radicals which are composed mainly of hydrogen and carbon, and include such radicals which contain, in addition, minor amounts of substituents such as oxygen, nitrogen,

carbon lubricants, e. g., lubricating oils derived from coal products. Other synthetic oilsinclude esters of acetylated propene oxidepolymers prepared by acetylating propene oxide polymers. containinghydroxyl groups, dicarboxylic acid alkylene oxide-type polymers, e. g.,

esters, polyesters, esters of polyhydric alcohols and liquid esters of acids of phosphorous and silicon.

The acyl ureas are used in amounts suliicient to thicken the base oils to the consistency of a grease; that is, in

- amounts of about 5% to about 40% by weight based on the final composition. With the greater proportion of the base oils, grease compositions are obtained when from about 15% to about 30% by weight of acyl ureas are incorporated in the base oils.

Acyl ureas and thioureas can be used in smaller amounts than those noted hereinabove. For example, approximately 2% octadecanoyl urea can be incorporated in a lubricating oil to thicken the oil slightly for use as an air cleaner oil.

The grease compositions of this invention are prepared quite similarly to other greases using other thickening agents; that is, the acyl ureas and the base oils are brought together in a mixing vessel, and with constant agitation, the mixture is heated up to temperatures ranging from 200 F. to 500 F., then cooled to room temperature. For the most part, the greases thickened with acyl ureas 1-hexyl-3-eicosanoyl thiourea,

Example 1.-Preparatin of octadecanoyl urea thickened grease A mixture of grams of octadecanoyl urea and 30 grams of a California solvent-refined paraflin base lubricating oil having a viscosity of 185 SSU at 210 F. was heated with agitation to 300 F., then cooled to room temperature.

The resulting grease was fibrous, and had a melting point of 290 F.

Example 2.-Preparati0n of octadecanoyl urea thickened grease A mixture of 10 grams of octadecanoyl urea and 22 grams of a California solvent-refined parafiin base lubricating oil having a viscosity of 480 SSU at 100 F. was heated to 300 F., with agitation, then cooled to room temperature.

The resulting grease was unctuous, and had a melting point of 295 F.

Example 3.Preparation of dodecanoyl urea thickened grease A mixture of 3 parts by weight of dodecanoyl urea and 10 parts by weight of a California solvent-refined paraffin base lubricating oil having a viscosity of 185 SSU at 210 F. was heated to 320 F., then cooled to room temperature.

The resulting grease composition was somewhat pasty, and had a melting point of 300 F.

Example 4.Preparati0n of octadecanoyl urea thickened grease A mixture of 27 parts by weight of octadecanoyl urea and 73 parts by weight of a tricresyl phosphate synthetic oil was heated to a temperature of 200 F., then cooled to room temperature.

The resulting grease composition was unctuous, and had a melting point of 230 F.

Example 5.Preparati0n 0f dodecanoyl thiourea thickened grease A mixture of 1 part by weight of dodecanoyl thiourea and 4 parts by weight of a California solvent-refined paraflin base lubricating oil having a viscosity of 185 SSU at 210 F. was heated to 250 F., then cooled to room temperature.

The resulting grease composition was moderately stringly, and had an ASTM unworked penetration of 315.

c mm:

1. A grease composition comprising a major proportion of an oil of lubricating viscosity and a minor amount, sufficient to thicken the oil to the consistency of a grease, of urea selected from the group consisting of aliphatic acyl urea and aliphatic acyl thiourea, wherein said urea contains a total of from 11 to 27 carbon atoms and not more than one aliphatic acyl group attached to a nitrogen atom.

2. A grease composition comprising a major proportion of an oil of lubricating viscosity and a small amount, sufiicient to thicken the lubricating oil to the consistency of a grease, of aliphatic acyl urea containing a total of from 11 to 27 carbon atoms and having no more than one aliphatic acyl group to a nitrogen atom.

3. A grease composition comprising a major proportion of an oil of lubricating viscosity and a minor amount, sufiicient to thicken the oil to the consistency of a grease, of aliphatic acy' urea having no more than one aliphatic acyl group attached to a nitrogen atom and wherein said aliphatic acyl group contains from 12 to 18 carbon atoms.

4. A grease composition comprising a major proportion of an oil of lubricating viscosity and a minor amount, sufficient to thicken the oil to the consistency of a grease, of aliphatic acyl thiourea having no more than one aliphatic acyl group attached to a nitrogen atom and wherein said aliphatic acyl group contains from 12 to 18 carbon atoms.

5. A grease composition comprising a major proportion of an oil of lubricating viscosity and from 5% to 40% by Weight of urea selected from the group consisting of aliphatic acyl urea and aliphatic acyl thiourea, said urea containing no more than one aliphatic acyl group attached to a nitrogen atom and wherein said aliphatic acyl group contains from 12 to 18 carbon atoms.

6. A grease composition comprising a major proportion of an oil of lubricating viscosity and from about 15 to about 30% of urea selected from the group consisting of aliphatic acyl urea and aliphatic acyl thiourea wherein said urea contains no more than one aliphatic acyl group attached to a nitrogen atom, and said aliphatic acyl group contains from 12 to 18 carbon atoms.

7. A grease composition comprising a major proportion of a petroleum base lubricating oil and from about 15% to about 30% of urea selected from the group consisting of aliphatic acyl urea and aliphatic acyl thiourea, wherein said urea contains no more than one aliphatic acyl group attached to a nitrogen atom, and said aliphatic acyl group contains from 12 to 18 carbon atoms.

8. A grease composition comprising a major proportion of a petroleum base lubricating oil and from about 15% to about 30% of dodecanoyl urea.

9. A grease composition comprising a major proportion of a petroleum base lubricating oil and from about 15 to about 30% of octadecanoyl urea.

10. A grease composition comprising a major proportion of a petroleum base lubricating oil and from about 15 to about 30% of dodecanoyl thiourea.

11. A grease composition comprising a major proportion of a petroleum base lubricating oil and from about 15 to about 30 of octadecanoyl thiourea.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,937,463 Nill Nov. 28, 1933 2,594,286 Bryant et al Apr. 29, 1952 2,595,556 Worth et al. May 6, 1952 

1. A GREASE COMPOSITION COMPRISING A MAJOR PROPORTION OF AN OIL OF LUBRICATING VISCOSITY AND A MINOR AMOUNT, SUFFICIENT TO THICKEN THE OIL TO THE CONSISTENCY OF A GREASE, OF UREA SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC ACYL UREA AND ALIPHATIC ACYL THIOUREA, WHEREIN SAID UREA CONTAINS A TOTAL OF FROM 11 TO 27 CARBON ATOMS AND NOT MORE THAN ONE ALIPHATIC ACYL GROUP ATTACHED TO A NITROGEN ATOM. 